A flaw in Pacemaker allows an unauthenticated remote attacker to send a specially crafted compressed message that, before authentication, triggers an integer overflow during message decompression. This overflow corrupts memory and can bring the CIB remote listener process to a halt, resulting in a denial of service. The vulnerability is a classic integer overflow (CWE‑190).

Vulnerable platforms include Red Hat Enterprise Linux 6, 7, 8, 9, and 10, as well as Red Hat OpenShift Container Platform 4. The affected component is the Pacemaker CIB remote listener that listens on configured remote ports.

The CVSS score of 8.6 classifies this flaw as a high‑severity vulnerability. The EPSS score of less than 1 % indicates that exploitation is currently unlikely, and the flaw is not listed in the CISA KEV catalog. However, because the attack vector is remote and unauthenticated, an attacker only needs network reach to the listener’s port to exploit it, making it potentially hard to detect without monitoring for process crashes. The primary risk is service disruption rather than data compromise.